Having been in the antiques/collectibles business for almost 30 years I am noticing that items which were bringing big bucks even just 3 or 4 years back have now flatlined.
Values of many items have plummeted. What I am seeing is that many collectors are paring down and cutting out spending on "unneeded" items. Not to mention the fact that new collectors just are not around as much as they used to be,both in the antiques/collectibles area and the chip area.
Your prices seem reasonable but.....I think that people are looking for bargains and 20% of "book value" will not cut it anymore as there are bargains to be had everywhere and...to be honest....book value and desirability are two different things. And then of course,we have two different book values,we have shows and we have the dreaded eBay.
There are just too many chips out there and too few collectors.
If you can afford to hang onto your better chips then perhaps it would be wise to do so and hope that the value returns.
Other than that...perhaps eBay,with lower starting prices and no reserve and let the chips fall where they may price wise or,if they are real good chips,then a club auction could work as well.